If I ease into the throttle slowly the car is fine, but if you step on the gas hard it hesitates for a second and then takes off. Any ideas?

-New cat 100 miles ago
-Maintained to spec

If you've had this happen let me know and also what you did to fix it.

 

How many miles on the car and any cels?

 

92k, no check engine lights. No fluid leaks. air filter is a few months old. Fuel filter is probably a year old. Primary oxygen sensor is a few months old too. Cleaned the maf when I did the air filter. Rear o2 is disconnected but that's disabled in HPT.

 

I had the fuel pump recall done. Definitely isn't a weak fuel pump.

MAP sensor?

 

Naaw usually if It's a sensor it will throw a code. I was going to say maf. But you said no codes so I'm not sure

 

Yeah I'm stumped as well. I thought it was the cat but when I took it off it wasn't clogged at all. Replaced it anyway.

 

Have access to someone with hpt?

 

what spark plugs do you have? look into that.
I would also say MAF and or cat, but looks like you already did them.

 

i dont know lsjs, but dirty throttle body?

 

Nah the tb is clean. It also seems to have a rough idle once it's warmed up too.

I used to have hpt but not anymore. Idk anyone close who has it either.

Bkr7eix

 

If you got no cels, everything els is new/clean and in good shape, look into your timing chain? Buy a kit maybe. Might be streched enough to make the motor feel lazy

Just trying to think a little outside the box here. Its not the obvious things. Btw i dont know lsj, but can ypu service your fuel filter? That was HUGE when i did mine

 

The fuel filter is pretty new. I think it's a boost leak I can hear it when I step on the gas.

 

Chain is fine..check vac lines to bypass valve

 

Spark Plugs Good ? Are They Gapped To Specs ?

 

Check the butterfly valve on the sc, sometimes they stick. Not the bypass valve, but the valve on the actual sc

 

My vacuum lines were reversed on the replacement blower. Switched them and all is well. Mileage is up too lol

 

check for rust inside the coils under the spark boot wire. there could be rust on the screw for which you will get this symptom. if that checks out ok, throttle body will be the issue.

 

Cool never thought to check something like that. You mean where the coil connects to the spark plug tip?

Thanks a lot.

 

I have rust on mine, and this exact problem. Could you please elaborate on the fix? I assume it's new coil packs?

Thank you!

 

Use a Phillips screw driver.
Remove screw
Polish rusted screw with 1000 grit sand paper
Reinstall screw
Coat screw head with dielectric grease
Reinstall

 

Ahh, so I assume I push the screwdriver up into the "pencil" or boot? And there's a screw head up at the top of the spring?

Thanks!

PS: I'm looking to try new plugs, would yours work well on a 2.8? What gap did you use and what gap do you recommend? Thanks

 

not on top of the spring, but where the spring mates with the coil

 

FIXED!

I was having two problems:

1. Car felt like it hit a brick wall, no power at all, usually at 4K RPM, then it would buck it's way up to 6K. Brutal.
2. Noticeable hesitation on boost and off boost when high in the RPM range.

The fix to this was:

• Replaced the fuel pump
• Replaced the fuel filter
• Used 1000 grit sandpaper to scrub the spring/coil inside the boot of each coil pack
• Carefully applied dielectric grease to the inside boot of each coil pack (the grease is an insulator)
• Installed BRK7EIX-11 spark plugs (NGK) gapped at 0.040 (while the plugs are cold!)
• Ran Seafoam through the vacuum lines twice

Problems solved, no hesitation to 7k redline, ran the car for 1.5 hours, just like new!